What to Do About Low Progesterone

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Low progesterone is an unusually low level of the female sex hormone progesterone. Symptoms can include heavy bleeding, irregular periods, and miscarriage. Low progesterone in pregnancy can result in preterm delivery. This article discusses the meaning of low progesterone, its symptoms, and the conditions it can lead to. This article also explains when to seek treatment.

Sex and gender terms

Sex and gender exist on spectrums. For the purposes of this article, we use “male” and “female” to refer to a person’s sex assigned at birth.

What does progesterone do?

young adult female outside, gazing up at the scenery
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The hormone’s name is a clue to what it does. Progesterone is pro-gestational. It acts to prepare a female’s uterus for pregnancy and maintains pregnancy after it occurs. Progesterone plays a role in several nonreproductive functions as well. These include bone formation and mood.

Males also produce progesterone, but much smaller amounts than females. In males, progesterone is a building block for testosterone and also helps with nonreproductive functions.

In females, progesterone levels change during the menstrual cycle and over a lifetime. The menstrual cycle has two main phases: the follicular phase and the luteal phase. Day one of the cycle starts with menstruation. Then, the follicular phase begins. A follicle grows and releases an egg during ovulation.

After ovulation occurs, the luteal phase begins. In this phase, the follicle degenerates into a remnant called the corpus luteum. The corpus luteum makes progesterone, which stimulates the lining of the uterus to grow and thicken. This makes a rich environment for a fertilized egg to implant.

If fertilization and implantation do not take place, the corpus luteum degrades and stops making progesterone. This signals the uterine lining to shed, and menstruation takes place again.

If a fertilized egg implants, the corpus luteum keeps making progesterone. The hormone continues to stimulate the uterine lining to make blood vessels to nourish the embryo. The corpus luteum also supports the development of the placenta. Eventually, the placenta will take over progesterone production.

Progesterone levels rise throughout pregnancy and are about 10 times as high in a pregnant female as in a female who is not pregnant.

What is low progesterone?

Low progesterone means a lower than usual level of progesterone in the bloodstream. In females, low progesterone levels cause problems with menstruation, fertility, and maintaining pregnancy.

Low progesterone is also a potential marker of luteal phase deficiency, which is a luteal phase lasting 10 days or fewer. A typical luteal phase lasts 12–14 days.

Females may have low or no progesterone when their ovaries are not working as usual. This occurs naturally with aging and menopause. It can also happen with certain conditions, such as hypothyroidism, a low level of thyroid hormone.

How much do you know about menopause? Get the facts here.

Does low progesterone cause symptoms?

Symptoms of low progesterone are the result of not having enough of this hormone for regular menstruation, fertilization, and pregnancy.

Common low progesterone signs and symptoms include:

Talk with your doctor promptly if you have symptoms that could indicate low progesterone levels. It is important to find the cause of unusual bleeding and other problems with menstruation and pregnancy. There can be conditions more serious than low progesterone causing these issues.

Having low progesterone levels can allow estrogen — the other major female sex hormone — to act unopposed. Progesterone and estrogen usually work in balance with each other. Unopposed estrogen can cause weight gain, low sex drive, and gallbladder problems.

Another concern when estrogen is the dominant hormone is endometrial cancer.

Low progesterone can also prevent females from achieving peak bone density. This increases their chance of osteoporosis, which is thinning of the bones. 

Can you get pregnant with low progesterone?

Progesterone promotes pregnancy, so a low level of progesterone may reduce the likelihood of conceiving.

Learn more about fertility and conception here.

Can low progesterone cause pregnancy loss?

Low progesterone can cause early pregnancy loss and recurrent pregnancy loss, but there are other possible causes. Talk with your healthcare professional about

Learn more about the typical frequency of pregnancy loss and possible causes here.

What causes low progesterone?

Progesterone is a sex hormone that is under the control of the hypothalamus and pituitary gland in the brain. The hypothalamus stimulates the pituitary gland, which stimulates the ovaries to make progesterone. If anything goes wrong in that chain, low progesterone can occur.

Some factors increase the chance of developing low progesterone. These include:

Reducing your risk of low progesterone

It is not always possible to prevent low progesterone levels. However, you may be able to address the factors that can cause it. For females near menopause, this may involve hormone replacement therapy (HRT). Talk with your doctor to understand the potential benefits and risks specific to you.

Get fast facts about HRT here.

How do doctors diagnose low progesterone? 

To diagnose low progesterone, your doctor will take a medical history, perform an exam, and order testing. The physical exam will likely include a pelvic exam to rule out other causes of your symptoms.

A blood test can tell your doctor whether or not your progesterone levels are low. A normal result depends on where you are in your menstrual cycle and if you are pregnant or menopausal. The lab will give you a reference range that will tell you where your level falls.

Your doctor may need to test your progesterone level multiple times to make an accurate diagnosis.

Questions your doctor may ask include:

  • What symptoms are you experiencing?
  • How long have you had these symptoms?
  • Are you still having menstrual periods? Are they regular?
  • When was your last menstrual period?
  • Is there a chance you could be pregnant?
  • What medical conditions do you have?
  • What medications do you take?

How do you treat low progesterone? 

Treatment for low progesterone depends on the suspected cause and the symptoms or conditions you are experiencing. Treating the underlying cause, such as an underactive thyroid, may resolve the issue.

To treat low progesterone levels, doctors can prescribe progesterone supplementation. Progesterone is available in forms you take by mouth, vaginally, or by intramuscular injection. Synthetic, manufactured forms of progesterone are known as progestins, or progestogens.

There can be side effects from progestins, including:

  • bloating
  • headache
  • breast soreness
  • moodiness
  • breakthrough bleeding, for females past menopause
  • cramps, for females still menstruating and taking progestin birth control
  • increased blood pressure
  • low blood sugar

Progesterone supplementation, infertility, and pregnancy loss

Low progesterone is a possible marker of luteal phase deficiency, which has been associated with recurrent pregnancy loss and infertility.

Studies on progesterone supplementation as a treatment for recurrent pregnancy loss have shown mixed results, according to the American Society for Reproductive Medicine (ASRM). Some studies show it can reduce the rate of pregnancy loss, but another study did not show this effect.

Progesterone supplementation is appropriate after fertility treatment. However, there is no clear evidence that supplementation benefits females with natural menstrual cycles, notes the ASRM.

Outlook

If you have signs and symptoms of low progesterone, increasing levels with a synthetic hormone may relieve your symptoms. First, however, your doctor will address other possible causes of your symptoms. Your doctor also will discuss the potential side effects of hormone replacement.

Females with low progesterone and associated fertility problems or pregnancy loss should discuss their diagnosis and treatment options with their doctor.

Summary

Low progesterone is having a lower amount of progesterone hormone than is usual. This may or may not cause noticeable symptoms. Problems with menstruation, fertility, and maintaining pregnancy can be related to low progesterone levels.

Your medical professional can determine your progesterone level from a blood sample. Because the level of progesterone changes throughout your cycle, you may need several measurements to know with certainty if you have low progesterone.

If low progesterone causes symptoms, you can take a synthetic form to increase the progesterone levels. These medications, known as progestins, can cause side effects. Your healthcare professional can help you understand the pros and cons of low progesterone treatment.

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